There is no doubt about it. Thirty-second notes [8 note groupings] are hard. It took quite a bit of time to come up with something that was interesting, wasn't to difficult and didn't sound like a never ending roll or 2 sets of 16th notes per beat. It will be helpful to review the single beat basics that don't start on or have notes on the downbeat.
This piece starts off simply and get's really interesting at m.11. Watch out for m.13 b.3. The tempo is kinda fast, it didn't sound very good to far from the tempo at which I originally wrote it. Download the midi file, and change the tempo in your program of choice and then work your way up.
Download the original Midi file. Size: 2.6k
Hear the etude played at 57bpm. Time: 0:50